With the increase in the functionality and the number of available functions in equipments incorporating semiconductor devices, the integration density and the scale of semiconductor chips are increasing and the number of electric solder joints (generally solder joints) that connect a semiconductor package incorporating a semiconductor chip to a circuit board is increasing to a large extent. Accordingly, the solder joints of a semiconductor package become more apt to be deteriorated by thermal-fatigue (thermal fatigue fracture) since the solder joints receive thermal stress repeatedly.
To prevent thermal fatigue fracture of solder joints, a method for detecting upcoming thermal fatigue fracture of solder joints has been proposed (refer to JP-B2-3265197, for example). In this method, sensor bumps that electrically connect the semiconductor package side to the circuit board side are provided separately from original bumps for electrical connection. An electrical resistance value of a connection path including the sensor bumps are detected automatically. It is determined that the solder joints are approaching thermal fatigue fracture when a detected electrical resistance value has exceeded a given level.
The above-described thermal fatigue fracture detecting method which is proposed by the publication JP-B2-3265197 has a problem that a remaining life of solder joints of a semiconductor package cannot be determined though their upcoming thermal fatigue fracture can be detected.
Furthermore, where damage prediction is made before use of an electronic device or damage prediction is made based on a parameter measured during use of an electronic device, it should be taken into consideration that differences exist between individual electronic device and individual components and members such as functional components mounted and solder joints. In addition, the fatigue characteristic of the solder joint has a variation. Therefore, actual damage values of the solder joints have a large variation and may be much different from a damage prediction value.